Electric lamp



Aug. 26 1924. 1,506,071

S. M LUCAS ELECTRIC LAMP Original Filed March 9. 1920 2 Sheets-Sheet. l

To Somzoz: OF ALTERNATING CURRENT.

M ATTORNEY Aug. 26 1924.

. 1,506,071 s. M. LUCAS ELECTRIC LAMP Original Filed March 9. 1920 2 Shoots-Shoat. 2

\ 6 INVENTYOR 1 1'5 W. flan 17 a- 21420.12

AL; ATTORNEY Patented Aug. 26, 1924.

UNITED STATES PATENT OFFICE.

SAMUEL LUCAS, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION .SWI'ICH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA.

Continuation of application Serial No.

To (ZZZ whom it m my concern Be it known that I, SAMUEL M/Loons, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and Stateof Pennsylvania, have invented certain new and useful Improvements in Electric Lamps, of which the following is a specification.

My invention relates to electric lamps, and has for an object the provision of means for indicating at a distant point whether or not a lamp is lighted.

Broadly stated, I accomplish this object by using for a lamp a rectifying device having a filament and an anode, the filament serving as the luminous element of the lamp. The indication means is controlled by a circuit which includes the filament and anode as well as a source of alternating current. Inasmuch as current can flow in such circuit only when the filament is hot, it follows that the indication means will respond only when the filament is actually lighted.

Apparatus embodying my invention is capable of general application, but is particularly well adapted for accomplishing the desired return indication when light signals are used in interlocking systems for railways, that is, systems wherein a group of switches and signals are controlled from a central point by an interlocking machine.

In connection with interlocking apparatus, it is well understood that means must be provided for locking each signal lever in. a preliminary or indicating position while moving from proceed towards stop position, and for releasing the lever only when the signal controlled thereby has assumed the stop aspect in response to the preliminary movement of the lever. The releasing means is usually termed the indication device.

lVhen signals of the light type are employed in interlocking apparatus, each signal usually comprises at least two electric lamps of the incandescent.filament type, which indicate stop and proceed, respectively, when illuminated, the circuits for the lamps being controlled by contacts actuated by the signal lever. It follows, then, that means should be provided for operating the indication device on the lever only when the stop lamp is illuminated.

When in 7 invention is a lied to a -ara- 364,485, filed March 9, 1920. 1921. Serial No. 494,823.

ELECTRIC LAMP.

This application filed August 24,

tus of this character, I provide means for releasing the lever from indicating position only when the filament of the stop lamp is actually hot enough to give the stop indication.

The present application is a continuation of my co-pending application, filed on the 9th day of March, 1920, Serial No. 364 185, for railway tratfic cont-rolling apparatus, in so far as the subject matter common to the two is concerned.

I will describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 a diagrammatic view showing one form of apparatus embodying my invention. Fig. 2 is a fragmental view showinga modification of part. of the indication device shown in Fig. 1. 3 is a view showing another form of indication device which may be substituted for the device shown in Fig. 1. Fig. 4 is a view similar to Fig. 1 but show ing a modification of the apparatus illustrated the-rein. Fig. 5 is a View showing an alternative form of indication device which may be substituted for the device shown in Fig. 41. Fig. 6 is a view showing still another modification of. the apparatus shown in Fig. 1. Fig. 7 is a view showing a position light signal having applied thereto one form of apparatus embodyingmy invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first .to Fig. 1, the reference character S designates a railway signal comprising two electric lamps G and R. Lamp G is an ordinary incandescent filament lamp, whereas lamp R- is in the form of a rectifier comprising a filament 3 and an anode 4,

both of which are enclosed in a bulb from which the air has been exhausted. The filament 3 constitutes the luminous or lighting element of the lamp R. Located in front of the lamps G and R, respectively, are two lenses 2 and 2 which are preferably colored green and red, respectively, and each of which serves to project a beam of light from the corresponding lamp when, the lamp is illuminated. In accordance with usual practice, the signal indicates proceed when lamp G is illuminated, and stop when lamp R is illuminated, the indication, of course, being determined by the color of the light beam projected by the signal.

The lamps in signal S are controlled by a lever L, which is usually one of a plurality of similar levers in an interlocking machine. As here shown, this lever is mounted to slide longitudinally, and it is provided with a grip 5 to facilitate manipulation by hand. In accordance with usual interlocking practice, the lever L has three controlling positions, known as reverse, indicating and normal positions, respectively. The con trol of the signal is such that the proceed lamp G is illuminated when the lever is in the reverse position, and that the stop lamp R is illuminated when the lever is in the indicat-ing" and normal positions. As shown in the drawing, the lever is in the reverse position, the circuit for the proceed lamp G being from the secondary of a transformer T through wire 15, contact 68 on lever L, wire 16, lamp G, wire 17, and common wire 0 to the secondary of transformer- T The primary of transformer T is supplied with operating or lighting alternating current from a source which is not shown.

When lever L is moved to the left from the position shown in the drawing, it is arrested in the indicating position by the en-- gagement of a latch 11 with a shoulder 21 on the lever. This movement of the lever opens contact 6-8 and closes a contact 6-9, so that the proceed lamp Gr, becomes extinguished and current-1 is supplied to an auto transformer U, the circuit being from the secondary of transformer T through wire 15, contact 69, wires 18 and 1S, winding of auto transformer U, and common wire 0 to the secondary of transformer T Filament 3 of stop lamp R is connected across a portion of the winding of the auto transformer, so that this lamp is then lighted. I

While the lever is in the indicating position, an indication circuit is closed, which circuit passes from the secondary of transformer T through wire 15, contact 6-9, wire 18, wire 19, contact 107, wire 20, primary of an indication transformer T indication wire I, anode a and filament 3 of lamp R, and common wire 0 to the secondary f transformer T If filament 3 is hot enough to radiate the proper amount of light for signal purposes, current will flow in. this circuit in one direction, that is, from anode to filament, but not in the other direction, so that the primary of transformer 'i is supplied with a rectified or pulsating direct current which varies from Zero to maximun'i and back to zero in the time re quired for one-half of a complete cycle of the operating current from transformer T. It follows that this pulsating current will induce in the secondary of transformer T an alternating current having a large component the frequency of which is twice that of the current delivered by transformer T. A composite current having the fundamerr tal component and acomponent of twice the fundamental frequency is delivered to the stator winding 14- of an induction motor M the rotor 13 of which operates a centrifugal device C. This centrifugal device 0 in turn actuates the latch 11 in such manner as to lift this latch out of the path of shoulder 21 when the centrifugal device opcrates at a predetermined speed. Inasmuch as motor M is of the induction type, its speed will be between the speed corresponding to the fundamental frequency and that corresponding to the higher frequency. The centrifugal device C is so adjusted that whenit is driven at this speed it will elevate the latch 11, but that if'motor M should be operated by current of the frequency supplied by transformer T, the latch 11 will not be elevated.

After the indication has been received, that is, after latch 11 is elevated, the lever L may be moved still farther to the left to its normal position wherein contact 7.10 is opened so that motor M is de-energized.

If the wave shape of the current inthe I secondary of transformer T be analyzed, it will be found to comprise the fundamental wave (the wave shape of the current from transformer T predominating, and a second harmonic of nearly equal magnitude. If desired, the scheme shown in Fig. 2 may be employed, wherein a selective device X comprising reactances 22, 22 and condensers 23, 23 is interposed, between transformer T and motor M to tune out the fundamental wave and leave only the second harmonlc to operate the motor.

As with the apparatus shown in Fig. 1, motor M must be operated at a speed corresponding to twice the frequency of the signal operating current in order to release the lever L. The advantage of the structure shown in Fig. 2 is thatdue to the elimination. of the fundamental wave, the motor will operate at higher speed than is the case with the arrangement shown in Fig. 1.

Referring now to Fig. 3, l have here shown a modification of the device controlled by the indication current for releasing the lever L. In this modification the latch 11 is elevated by the armature 51 of a polarized magnet P, which in turn is en-. ergized directly from the indication circuit. This magnet P is so arranged that it will elevate the. latch only when energized by direct or pulsating current which flows from anode 4 to the filament 3 in lamp R. It follows that this indication device will not respond to stray alternating current, or to alternating current from transformer T.

Referring now to Fig. 4, the lamps G and R are controlled by lever L in the same manner as in Fig. 1, except that the primary of the indication transformer T is included in the signal control wire leading from lever contact 9 to the auto transformer U. The anode 4 is connected to wire 18 through a resistance 24, so that when contact 69 is closed and filament 3 is hot, a pulsating current flows through the primary of transformer T and resistance 24 to the anode, which current, in transformer T" is superposed on the operating current supplied to the filament. The result in the secondary of transformer T is an electromotive force which, when analyzed, will be found to comprise the fundamental wave and a second harmonic of considerable magnitude. The fundamental wave is tuned out by a selective device X, which is similar to the device shown in Fig. 2, so that motor M is supplied with an alternating current of twice the frequency of the operating current. Latch 11 is controlled by motor M in the same manner as in Fig. 1.

The structure shown in Fig. 4 is so arranged that motor M and centrifuge C operate continuously to elevate the latch 11 when the stop lamp R is illuminated. If desired, therefore, the centrifugal device may be used to give a positive and continuous indication at the interlocking machine that the signal indicates stop. As here shown, this is accomplished by a red lamp R and a green lamp G located adjacent the lever L, which lamps are controlled by a contact finger 25 operatively connected with the latch 11. When the signal indicates proceed, that is, when red lamp E is extinguished, the latch 11 is depress-ed, so that contact finger 25 engages with a fixed contact 26 and thereby completes a circuit including the green lamp G, which circuit will be obvious from the drawing. On the other hand, when the stop lamp R is illuminated, latch 11 is elevated so that contact finger 25 engages with a fixed contact 27 to complete a circuit through the red lamp R This arrangement gives a continuous indication at the machine that the signal is at stop, and it instantly indicates the'occurrence of a failure of the stop lamp R due to any cause whatsoever.

Referring now to Fig. 5, I have here shown a modified form of indication apparatus which may be substituted, if desired,

for the apparatus shown in Fig. 4. If the current in the primary of transformer T in Fig. 4 be analyzed, it will be found to comprise a direct current component and an alternating current component. The apparatus shown in Fig. 5 is designed to require the presence of both of these components in order to release the lever from the indicating position. latches 11 and 11, which coact with shoulders 21 and 21, respectively, on the lever L. These latches are controlled by two armatures 28 and 28 respectively, which armatures are in turn controlled by an electro magnetic device A. The device A comprises two magnetizable cores 29 and 30 connected by two magnetizable bridges 32 and 33, the cross-sectional area of the latter being compa-ratively small. The cores 29 and 30 are provided with a winding 31 which is in cluded in the signal control wire 18-18" in the same manner as the primary of trans former T in Fig. 4. The cores 29 and 30 are provided with copper bands 35 and 36 respectively, and a similar band 34 surrounds the bridge 32.

Each armature 28 and 28 is biased to the open position wherein the latch controlled thereby is depressed, hence it follows that lever L can be released only when both ar-,

matures are closed. Assuming now that the stop lamp R is illuminated, the greater part of the alternating component of the magnetic flux due to the current in winding 31 will be forced away from armature 28 due to bands 35 and 36, and will be forced through armature 28 due to the band 34 on bridge 32, so that this flux will cause armature 28 to close but will not affect armature 28*. The direct component of the flux will, however, be shunted away from armature 28 by bridge 32 and will be forced through armature 28 owing to the high reluctance of bridge 33, so that this flux will close armature 28 but will not affect armature 28. It. will be seen, therefore, that both armatures are closed only when the current flowing in winding 31 comprises a direct component and an alternating component, that is, only when the signal operating current in this winding is modified by the rectified current taken by the resistance 24 and the anode 4 of the stop lamp.

As shown in Fig. 5, the armatures 28 and 28? are employed to control two auxiliary lamps Gr and B the functions of which are the same as those of the corresponding lamps in Fig. 4. For this purpose arn'iature 28 is provided with a contact finger 25 and armature 28 is provided with a similar contact finger 25 WVhen .both armatures are open, that is, when the signal indicates proceed, the green lamp G is illuminated, owing to the fact that contacts 26 are bridged by contact finger 25, and contacts 26 are bridged This apparatus comprises two ondary of transformer T by contact finger 25. When both armatures are closed, however, that is, when the signal indicates stop, the red lamp R is illuminated, owing to the fact that contacts 27 are bridged by contact finger and contacts 27 are bridged by contact finger 25. It will be seen, therefore, that if the stop lamp R is extinguished for any reason whatsoever, one or both of the armatures 28, 28 will open, so that the auxiliary lamp R will be extinguished. 7

Referring now to Fig. 6, I have here shown means for utilizing both halves of the wave of the operating current for indication purposes. The red or stop lamp, which is here designated R contains two anodes 41 and 4c". The filament 3 in this lamp is, in this instance supplied with current by the secondary of a transformerB, the primary of which is controlled by contact 69, on lever L in the same manner as "the auto transformer U in Fig. 1.

same manner as in Fig. 1.

The two anodes 4 and ll? are connected with the terminals of the primary of transformer B by wires 38 and 39, so that the potentials of these anodes alternate with the potentials of the terminals of the sec- The indication wire I is in this case connected with the filament 3, whereas wire 20, which leads from the primary .of transformer T passes to contact 10. Lever contact 7 is connected by a wire with the middle point of a reactance 37 the terminals of which are connected across the secondary of transformer T.

I will now assume that the lever L is moved to the left to the indicating position,

and that the filament 3 becomes hot enough to display the proper signal. During one half of a cycle of the current supplied by transformer T the anode P will be positive, whereupon current will flow from the sec ondary of transformer T, through common wire 0, wire 38, anode 4t, filament 3, indication wire 1, primary of transformer T wire 220 contact 10-7, wire 40, and the right hand half of reactance 37 to the right-hand terminal of the secondary of transformer T. During the succeeding half cycle anode 4t will be positive, so that current will then flow from the right-hand terminal. of the secondary of transformer T through wire 15,

contact 6-9,.wire 18, wire 39, anode 4 filament 3, indication wire I, primary of transformer T wire 20 contact 107, wire 1-0, and the left-hand half of reactance 37 to the secondary of transformer T. During this latter half cycle anode P is negative with respect to the filament, so that no current flows in, the circuit first traced. Similar- 'ly, during the first half cycle anode 4: is

negative with respect to the filament, so that no current flows in the second circuit. The

The pro-' ceed lamp G is likewise controlled in the transformer T.

result of this alternate action of the two branches of the indication circuit is to produce pulsating current in the primary of transformer T which varies from zero to maximum and back to Zero in the time required for the operating current to pass through one-half of a cycle. It follows that the frequency of the electromotive force induced in the secondary of transformer T is twice the frequency of the operating current delivered by transformer T. The fundamental wave is entirely absent, so that a frequency'selective device, such as that shown in Fig. 2 is not required. The control of the latch 11 is exactly the same as in Fig. 1.

I Referring now to Fig. 7, I have here shown my invention as applied to what is known as a position light signal. The signal, which is here designated S", comprises a plurality of electric incandescent lamps Gr, arranged in a vertical row, and a plurality of other lamps R, arranged in a horizontal row, a special lamp R, which is known as the pivot lamp, being common to the two rows. Vhen the lamps in the vertical. roware illuminated, the signal indicates proceed, and when the lamps in the horizontal row are illuminated, the signal indicates stop. As here shown, the lamps in the horizontal row and the pivot lamp R are each in the form of a rectifier having an anode 4, whereas the lamps in the vertical row, with the exception of the pivot lamp, are ordinary incandescent lamps.

The filament of the pivot lamp It is constantly illuminated byvirtue of current supplied thereto from the secondary of a The primary of this transformer is constantly supplied with current from transformer T", the circuit being through wires 15 and 4-1, primary 0 transformer T, wire 4-2 and common wire 0. When the lever L is in itsreverse po sition, wherein it is shown in the drawing, the proceed lamps are illuminated, the circuit being from the secondary of transformer T, through wires 15 and 15, contact 68, wire 16, thence through the filaments of the three lamps G in multiple to wire 17, and from this wire through common, wire 0 to thesecondary of transformer T The filament ofeach stop lamp R is sup-plied with current by a separate secondary winding in a transformer T. The circuit for the primary of transformer T? is from the secondary of transformer T, through wires 15 and 15, contact 69, wires 18 and 18, primary of transformer T, wire 50 and common wire 0 to the secondary of transformer T. v

It will be seen from the foregoing that the proceed lamps are illuminated when lit) the lever is in its reverse position and that the stop lamps are illuminated when the lever is in indicating and normal positions.

The indication circuit for the primary of transformer T" passes from the left-hand terminal of the secondary of transformer T, through common wire 0, wire 43, anode 4L, and filament 3 of the left-hand lamp It, wires n and 4-5, anode and filament of pivot lamp R, wires 16 and d7, anode and filament of the middle stop lamp It, wires 48 and i9, anode and filament of the right hand lamp It, indication wire I, primary of transformer T wire 20, contact 7-10, wire 18, contact .96, and wires 15 and 15" to the secondary of transformer T. It will be noted that this indication circuit includes in series the anode and filament of each lamp in the. horizontal. row, so that current will be supplied to transformer T only when the filament of each .of these lamps is actually hot enOugh to give the proper visual signal. During the half cycle when the common wire 0 is positive .with respect to wire 18, a current will flow through the indication circuit, which current Will have the same characteristics as the indication current in the structureshown in Fig. l. The fundamental wave in the electromotive force induced in the secondary of transformer T may be tuned out by a selective device X, so that the current supplied to motor M is of twice the frequency of the operating current. The control of latch 11 by motor Mis the same as in Fig. 1.

Although I have herein shown-and described only certain forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my. invention, what I claim is:

1. In combination, an electric lamp in the form of a rectifier having a. filament and an. anode, means for supplying lighting current to said filament, a device for indicat ing at a distance whether or not said lamp is lighted, and a circuit for controlling said device and including the filament and anode of said lamp and a source of alter nating current.

2. In combination, an electric lamp in the form of a rectifier having a filament and an anode, an auto transformer, said filament being connected across a portion of the winding of said transformer, means for supplying alternating current to said transformer, an indication device, and means connected with said anode and said transformer for controlling said device.

3. In combination, an electric lamp in the form of a. rectifier having a filament the form of a rectifier having a filament and an anode, means for supplying alternating lighting current to said filament,-an indication circuit supplied with current from said lighting source and including said filament and anode and the primary of a transformer, and indication means supplied with current from the secondary of said transformer and responsive to current of higher frequency than that of said lighting current but not to current of the frequency of the lighting current.

5. In combination, an electric lamp in the form of a rectifier having a filament and an anode, means for supplying alternating lighting current to said filament, an indication circuit supplied with current from said lighting source and including said filament and anode and the primary of a transformer, indication means supplied with current from the secondary f said transformer and responsive to current of higher frequency than'that of said lighting current but not to current of the frequency of the lighting current, and means'interposed between said transformer secondary and said indication means for tuning out current of said lighting frequency.

*6. In combination, a railway signal comprising a lamp in the form of a rectifier having a filament andan anode, a source of alternating current, a lever, means controlled by said lever for supplying operating current to said filament from said source, and indication circuit supplied with current from said source and including the filament and anode of said lamp, and looking meansfor said lever controlled by current in said indication circuit.

TJIn combination, a railway signal comprisinga lamp in the form of a rectifier having afilament and an anode, a source of alternating current, a lever, means controlled by said lever for supplying operating current to said filament from said source, an indication circuit supplied with current from said source and including the filament and anode of said lamp, means for locking said lever, and apparatus controlled by the current in said indication circuit. and -re sponsive to such current but not to the operating current supplied to said filament for releasing said locking means.

8. In'combination, a railway signal comprising a lamp in the form of a rectifier hav-' ing a filament and an anode, a source of alternating current, a lever having; proceed, indicating and stop positions, means controlled by said lever for supplying operating current to said filament from said source when thelever is in indicating and stop positions but not when it is in proceed position, an indication circuit supplied with current from said source and including said filament and anode, means for locking said lever in the indicating position while moving from the proceed towards the stop positions, and means controlled by the currentin said indication circuit for releasing said locking means.

9. In combination, a railway signal comprising a lamp in the form of a rectifier having a filament and an anode, a lever, means controlled by said lever for supplying operating current to said filament, an indication circuit including said filament and said anode and a source of alternating current, and locking means for said lever controlled by the current flowing in said indication circuit.

10. In combination, a light signal comprising a rectifier having a filament and an anode, an auto transformer, said filament being connected across part of the winding of said transformer, a source of alternating current, a lever for controlling the supply of current from said source to said transformer, a locking device for said lever, and electromagnetic means connected to said anode and to the winding of said auto transformer for releasing said lever locking device.

11. In combination, a railway signal comprising a rectifier having a filament and an anode, a source of alternating current, a lever, means controlled by said lever for supplying operating current to said filament from said source, an indication circuit supplied with current from said source and including the filament and anode of said signal and the primary of a transformer, a device for locking said lever, and electrical means receiving energy from the secondary of said transformer for releasing said lever locking device when energized by alternating current of twice the frequency of said source but not when energized by current of the frequency of said source.

12. In combination, a railway signal comprising a rectifier having a filament and an anode, a source of alternating current, a lever, means controlled by said lever for supplying operating current to said filament from said source, an indication circuit supplied with current from said source and including the filament and anode of said signal and the primary of a transformer, a device for locking said lever, a motor receiving energy from the secondary of said transformer, and a centrifugal device operated by said motor for releasing said lever locking device when the motor re ceives alternating current of twice the frequency of said source but not when the motor receives current of the frequency of said source.

13. In combination, a railway signal comprising a rectifier having a filament and an anode, a lever, means controlled by said lever for supplying operating current to said filament, an indication circuit including said filament and said anode and a source of alternating current, a locking device for said lever, and electro-responsive means controlled by said indication circuit for releasing said locking device.

14. In combination, a railway signal comprising a rectifier having a filament and an anode, a source of alternating current, a lever, means controlled by said lever for supplying operating current to said: filament from said source, an indication circuit supplied with current from said source and including said filament and anode and the primary of a transformer, a locking device for said lever, electrical means receiving energy from the secondary of said transformer. and responsive to current of twice the frequency of said alternating current source but not to current of the frequency of said source for releasing said locking device, and means interposed between said transformer secondary and said electrical means for tuning out current of the frequency of said source.

15. In combination, a light signal in the form of a rectifier having a filament and an anode, an auto transformer, said filament being connected across part of the winding of said transformer, a source of alternating current, an operating circuit including said source and said auto transformer and also the primary of, a second transformer, a resistance connected across said anode and a terminal of said auto transformer, a lever for controlling said operating circuit, a looking device for said lever, electrical means receiving energy from the secondary of said second transformer and responsive to current of twice the frequency of said source but not to current of the frequency of said source for releasing said locking device, and means interposed between said transformer secondary and said electrical means-for tun ing out current of the frequency of said source.

16. In combination, a light signal in the form of a rectifier having a filament and an anode, an auto transformer, said filament being connected across part of the winding of said transformer, a source of alternating current, an operating circuit including said auto transformer and said source and the primary of .a second transformer, a lever for controlling said operating circuit, a resistance connected across said anode and a third point in said auto transformer, a locking device for said lever, electrical means receiving energy from the secondary of said second transformer and responsive to current of twice the frequency of said source but not to current of the frequency of said source for releasing said locking device, and means interposed between the secondary of said second transformer and said electrical means for tuning out current of the frequency of said source.

17. In combination, an incandescent electric lamp comprising a filament and an an ode, a circuit including said filament and said anode as well as a source of alternating current and the primary of a transformer, a motor receiving energy from the secondary of said transformer, a centrifugal device operated by said motor, and indication means for said lamp controlled by said centrifugal device.

18. In combination, an incandescent electric lamp comprising a filament and an anode, an anode circuit for said lamp, a motor receiving energy from said anode circuit, a centrifugal device operated by said motor, and indication means for said lamp controlled by said centrifugal device.

In testimony whereof I afiix my signature.

SAMUEL M. LUCAS. 

